[Paraview] calculator tensor field

[Utkarsh Ayachit]

Gianna,

For Calculator filter,  names with "_X", "_Y" have special meaning.
Try change Calulators 1-9 to use Result Array names as "sigmaXX",
"sigmaYY", etc.
Does that work?

Utkarsh

On Mon, Oct 6, 2014 at 6:31 PM,  <Marschmann at stud.uni-heidelberg.de> wrote:
> Hello Utkarsh,
> thanks for looking at it.
> Attached is the state file:
> - Calculators 1-6 calculate the 6 independent components of the symmetric
> stress tensor sigma_ij
>
> - Calculators 7-9 calculate the traction vectors s_i from the stress
> components (s_i = sigma_ij e_j , summation over j implied, e_j basis
> vectors)
>
> Now in another calculator I'd like to compute the stress tensor field,
> either directly from the stress components sigma_ij or from the traction
> vectors. Both approaches fail with the error message.
> The stress tensor is given by
> sigma =
> sigma_xx(e_x*e_x)+sigma_yy(e_y*e_y)+sigma_zz(e_z*_ez)+sigma_xy)(e_xe_y+e_ye_x)+sigma_xz(e_xe_z+e_ze_x)+sigma_yz(e_ye_z+e_ze_y)
> equivalent to
> sigma = s_x*e_x + s_y*e_y +s_z*e_z
>
> Thanks,
> Gianna
>
>
>
> Quoting Utkarsh Ayachit <utkarsh.ayachit at kitware.com>:
>
>> Can you attach a sample data file/state file? That'll make it easier
>> to identify the problem and suggest a solution.
>>
>> Thanks
>> Utkarsh
>>
>> On Sat, Oct 4, 2014 at 4:14 AM,  <Marschmann at stud.uni-heidelberg.de>
>> wrote:
>>>
>>> Hello everyone,
>>>
>>> I have three displacement field vector components u, v, w in my .vtk file
>>> and wish to display the associated stress tensor.
>>> I made the following steps:
>>>
>>> - Apply the filter Gradient Of Unstructued DataSet
>>> -> Now have 9 scalars Gradient_0, ... , Gradient 8
>>>
>>> - compute components of stress tensor via sigma_ij = div(Gradient) +
>>> u_i,j
>>> -> Now have additional 9 scalars sigma_ij
>>>
>>> - from this form traction vectors:
>>> T_i = sigma_ij e_j   ,where e_j are the unit vectors iHat
>>>
>>> -> Now have three traction vectors from which the tensor field
>>> computation
>>> doesnt work:
>>>
>>> - I do Result = T_1*iHat + T_2*jHat + T_3*kHat for the tensor calculation
>>> and get the following error message:
>>>
>>> ERROR: In
>>>
>>> /home/abuild/rpmbuild/BUILD/ParaView-v4.0.1-source/VTK/Common/Misc/vtkFunctionParser.cxx,
>>> line 201
>>> vtkFunctionParser (0x205ddac0): Parse: Error deciding between ambiguous
>>> operators
>>>
>>>
>>> ERROR: In
>>>
>>> /home/abuild/rpmbuild/BUILD/ParaView-v4.0.1-source/VTK/Common/Misc/vtkFunctionParser.cxx,
>>> line 300
>>> vtkFunctionParser (0x205ddac0): expecting either 2 scalars or a scalar
>>> and a
>>> vector
>>>
>>>
>>> ERROR: In
>>>
>>> /home/abuild/rpmbuild/BUILD/ParaView-v4.0.1-source/VTK/Common/Misc/vtkFunctionParser.cxx,
>>> line 201
>>> vtkFunctionParser (0x205ddac0): Parse: Error deciding between ambiguous
>>> operators
>>>
>>>
>>> - Can you help me or tell me gow to visualize the stress tensor from the
>>> displacement field?
>>> - Alternatively you it would also be good to know how to multiply the
>>> result
>>> of  filter Gradient of Unstructured DataSet by a scalar value.
>>>
>>>
>>> Many thanks for helping!
>>> Gianna
>>>
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>>
>>
>>
>
>